This is the message you get when calling the same API endpoints as with 4.1. And in the vid they said that the older versions will be deprecated.

Your organization must be verified to use the model `gpt-5`. Please go to: https://platform.openai.com/settings/organization/general and click on Verify Organization. If you just verified, it can take up to 15 minutes for access to propagate.

And when you click that link the "service" they use is withpersona. So it is a complete shit show.